DESCRIPTION: The problem: Oral malodor causes much despair, and treatment is frequently empirical and ineffective because the specific cause is not usually known. The basic problem that has retarded progress in the treatment of oral malodor is the lack of an objective method for evaluating the severity of the condition, identifying the specific etiologies, and measuring response to treatment. [unreadable] [unreadable] A new solution to the problem: An advanced new breath test employing gas chromatography and mass spectroscopy (GC/MS) can detect low concentrations of volatile organic compounds (VOCs) in the breath. This breath test could identify the VOCs responsible for oral malodor, and determine whether treatment reduces their concentrations. [unreadable] [unreadable] Experimental plan to address the problem: The intensity of offensiveness of oral malodor will be rated by an organoleptic panel of human "sniffers" in two groups of human volunteers: subjects with oral malodor, and control subjects with no oral malodor. In addition, breath samples from all subjects will be analyzed by GC/MS, in order to identify the VOCs associated with oral malodor. [unreadable] [unreadable] The short-term Aim of the research is to correlate the subjective assessment by trained and calibrated odor judges with the objective results of a breath test, in order to identify the chemical composition of the VOCs responsible for oral malodor. The long-term Aims of the research are: 1) Diagnostic - to correlate specific causes of oral malodor (e.g. bacterial putrefaction on the dorsum of the tongue) with their breath VOC signature; 2) Therapeutic - to determine the effectiveness of treatments for oral malodor by measuring the reduction in the concentrations of breath VOC signatures; 3) Technological - to develop a mobile GC/MS instrument for breath analysis which could be employed in Dental and medical practices for the evaluation and treatment of oral malodor. [unreadable] [unreadable]